Thin-film transistor (TFT) flat-panel X-ray sensors are vital components in digital imaging technology, and applied in chest X-ray, CT (computed tomography) and other fields.
FIG. 1 shows a circuit configuration diagram of an amorphous-silicon TFT flat-panel X-ray sensor. The flat-panel X-ray sensor comprises a matrix composed of a plurality of pixel units. Each pixel unit comprises a photodiode 15 and a field-effect transistor (FET) 14. Each field-effect transistor 14 is connected to an adjacent gate scan line 12; each photodiode 15 is connected, via the FET 14 within a same pixel unit, to a data line 11 adjacent to that FET. In a matrix composed of a plurality of pixel units, for the respective FETs 14 in each row of pixel units, the gates are connected to a gate scan line 12 in that row, the sources are respectively connected to corresponding data lines 11, and the drains are connected to the negative terminals of the photodiodes 15. The positive terminals of the photodiodes 15 are respectively connected to bias lines 13. Each gate scan line is connected to a gate-control unit, and each data line 11 is connected to a source-control unit.
In the existing technology, 10 masking processes (photolithography processes) are usually needed to prepare an amorphous-silicon flat-panel X-ray sensor. The application of the masking processes makes the whole preparation procedure costly and complex; and the processes cause yield to decline and equipment capacity to decrease.